Reconciling subjective and objective cognitive decline using the Biber figure learning test

Abstract

•Background: Subjective Cognitive Decline (SCD), the perception of deteriorating cognition in the absence of apparent impairment on objective testing, has gained momentum in recent years as a risk marker for Alzheimer’s disease (AD). Traditional neuropsychological assessments, while typically inclusive of a verbal list-learning task, often do not include a comparable figure learning task. Emergent evidence suggests that nonverbal assessments may be particularly sensitive to the earliest cognitive changes associated with AD. The Biber Figure ••Learning Test (BFLT), a serial figure learning test and a nonverbal analogue to verbal list learning tasks, has been shown to associate with brain-based biomarkers of AD (e.g., hippocampal volume, amyloid load). This study investigates the utility of the BFLT for capturing SCD above and beyond other cognitive measures sensitive to AD progression. ••Participants and Methods: 88 community-dwelling, cognitively normal individuals participated in the study. SCD was assessed using a 20-item scale querying individuals’ perception of difficulty across a range of memory and non-memory abilities relative to others of their same age. Subscale scores on the BFLT, Loewenstein-Acevedo Scales of Semantic Interference and Learning (LASSI-L; a measure of verbal memory), Short-Term Memory Binding (STMB; a measure of short-term memory that utilizes a change detection paradigm), and Benson Complex Figure (BCF; a measure of visual memory) were examined as predictors of SCD. Regression analyses, adjusted for psychiatric symptom endorsement, were used to investigate the extent to which BFLT scores captured SCD beyond these other cognitive measures. ROC analyses were used to determine whether particular subscales could accurately differentiate between those with minimal-to-no SCD symptoms and those with more significant symptom endorsement (SCD- versus SCD+). ••Results: Unadjusted regression models indicated that lower performance on the BFLT trial 1 (T1) and retroactive interference (RI) associated with SCD beyond other measures. Adjusted models indicated that, in some instances, SCD is best captured when symptoms of depression are accounted for as well (higher symptom endorsement was associated with increased SCD endorsement). Adjustment for demographics (age, sex, education) did not change these findings. Although BFLT T1 demonstrated acceptable discriminability for SCD, no single cutoff met appropriate clinical standards. ••Conclusion: The present study’s impact is threefold. (1) It corroborates emergent evidence regarding the role of nonverbal memory in AD research. (2) It highlights the value of the BFLT, or simply T1, relative to other measures sensitive to AD. (3) It reinforces SCD’s usefulness as an inexpensive, non-invasive, and easily obtainable pre-clinical marker of AD